1 What is LMOD?
- 1.1 Modulefiles With vs Without Versions
2 LMOD Commands
- 2.1 Key changes - July 15, 2026
  - 2.1.1 1. Module Version Required
    - 2.1.1.1 How to Test This Change Early
  - 2.1.2 2. Changes to module spider
- 2.2 Showing the contents of a module
- 2.3 ml Shortcut
- 2.4 Shell Tweaks
3 Community Space
4 Further Information

What is LMOD?

Lmod is a Lua-based module system that easily handles the MODULEPATH Hierarchical problem. Environment Modules provide a convenient way to dynamically change the users’ environment through modulefiles. This includes easily adding or removing directories to the PATH environment variable. Modulefiles for Library packages provide environment variables that specify where the library and header files can be found. - LMOD

Modulefiles With vs Without Versions

Modules with Versions: Specific software stacks deployed with defined version numbers.

Example: slurm/compute2/23.02.5

Modules WITHOUT Versions: Core system tools or meta-modules that do not require explicit versioning.

Example: ris

LMOD Commands

To find out what modules are currently loaded, use the following command:

$ module list

To find out what modules are available to be loaded, use the following command:

$ module avail

Another way to search for modules is with the “module spider” command. This command searches the entire list of possible modules.

$ module spider

Users can check to see what is installed for specific software by adding the name of the software to the command.

$ module avail python

$ module spider python

To load packages, use the following command:

$ module load package1/version package2/version ...

To unload packages, use the following command:

$ module unload package1/version package2/version ...

To remove all modules, use the following command:

$ module purge

To go back to the initial set of modules, use the following command:

$ module reset

Key changes - July 15, 2026

1. Module Version Required

It is now required to specify the module version when loading any modules. For example, instead of using module load ucx, you must use module load ucx/1.14.1. Failure to specify the version will result in an error message.

Below is an example message when loading ucx without specifying the version:

$ module load ucx
Lmod has detected the following error:  These module(s) or extension(s) exist but cannot be loaded as requested:
"ucx"
   Try: "module spider ucx" to see how to load the module(s).

How to Test This Change Early

Export the following variables in a compute2 session

export LMOD_EXACT_MATCH='yes'

export LMOD_SHORT_TIME=86400

2. Changes to `module spider`

As the user cache has been removed, module spider can now only traverse modules that are currently visible in your $MODULEPATH. If a module is nested or dependent on a parent environment, you must load the parent module before searching for it.

Old Behavior

Running module spider matlab would find the software regardless of the current environment.

❌ module spider matlab

New Behavior

The relevant module path must be exposed prior to searching.

✅ module load ris & module spider matlab

Showing the contents of a module

To show the module functions instead of executing them, use the following command:

$ module show python

`ml` Shortcut

Instead of using module users can use ml instead. This is simply a shortcut command that has the same functionality as module.

$ ml

$ ml avail

$ ml load python/3.11.9

Shell Tweaks

Disable the user lmod spider cache to resolve occasional stack overflows with ml av
echo 'export LMOD_SHORT_TIME=86400' >> ~/.bashrc

Community Space

There are community spaces that users can install software into that can be loaded into LMOD. These are handled via Spack. There is documentation on how to use Spack here.

There is an RIS space that is the location of the TPHC bare-metal installed software. Find out more about the installed software here.

Spaces can be loaded like any software with LMOD.

module load ris

The spider command will only work for applications that are part of a community space when it is loaded.

E.g. Modules available in the ris space will only show up once it has been loaded.